U.S. patent number 4,136,554 [Application Number 05/847,228] was granted by the patent office on 1979-01-30 for tester for inflated items.
This patent grant is currently assigned to Wells Electronics, Inc.. Invention is credited to Raymond B. Larson.
United States Patent |
4,136,554 |
Larson |
January 30, 1979 |
Tester for inflated items
Abstract
A device for testing inflated objects such as tennis balls,
wherein a housing contains a testing chamber in which the inflated
object is compressed in a testing operation to an extent correlated
to its inflation pressure. Measuring means calibrated to indicate
inflation pressure are carried by the housing and include a sensing
member contacting the object being tested and displaced in said
testing operation from a normal position to an extent dependent
upon the inflation pressure of said object.
Inventors: |
Larson; Raymond B. (South Bend,
IN) |
Assignee: |
Wells Electronics, Inc. (South
Bend, IN)
|
Family
ID: |
25300122 |
Appl.
No.: |
05/847,228 |
Filed: |
October 31, 1977 |
Current U.S.
Class: |
73/81 |
Current CPC
Class: |
A63B
47/008 (20130101); G01N 3/40 (20130101); G01N
2203/0076 (20130101); G01N 2033/008 (20130101) |
Current International
Class: |
A63B
47/00 (20060101); G01N 3/40 (20060101); G01N
3/00 (20060101); G01N 33/00 (20060101); G01N
003/48 () |
Field of
Search: |
;73/78,81,85,52
;273/61D |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gorenstein; Charles
Attorney, Agent or Firm: Oltsch, Knoblock & Hall
Claims
What I claim is:
1. A device for testing the pressure of inflated objects
comprising
a housing having a test chamber formed in one end thereof and
adapted to receive an inflated object to be tested, said end
adapted to bear upon a supporting member, the depth of said chamber
being not greater than a dimension of said object,
a spring pressed plunger slidable in said housing and normally
positioned to project into said test chamber toward said supporting
member, and
means for measuring the displacement of said plunger from normal
position incident to compressive deformation of said object within
the confines of said test chamber between said plunger and said
supporting member when the chambered end of said housing engages
said supporting member.
2. A device as defined in claim 1, wherein said test chamber is
open to freely receive said object, is of a size to normally
receive a selected portion of the object and accommodates reception
of said compressively deformed inflated object therein as the
volume of said chamber is reduced to a predetermined extent.
3. A device as defined in claim 1, wherein said measuring means
includes an indicator pivoted to said housing and shifted by
movement of said plunger.
4. A device as defined in claim 1, wherein said measuring means
includes an indicator pivoted to said housing and engaged and
shiftable by said plunger, and a graduated pressure indicating
scale covered by said housing positioned adjacent the free end of
said indicator.
5. A device as defined in claim 1, wherein said plunger is slotted
to receive and guide a portion of said indicator.
6. A device as defined in claim 1, and
a transparent member carried by said housing and enclosing said
measuring means.
7. A device as defined in claim 1, wherein
said measuring means includes indicia correlated to and providing
readings of different ranges of pressure of an inflated object
being tested.
8. A device as defined in claim 1, wherein said housing includes a
liquid containing chamber into which a portion of said plunger
normally projects, and
said measuring means includes liquid level means for indicating
displacement of liquid incident to movement of said plunger in said
liquid chamber.
9. A device for testing the pressure of inflated objects
comprising
a housing having a test chamber adapted to receive only a part of
an inflated object and an open portion adapted to engage closing
means to close said chamber and having a testing condition when
said chamber is closed which causes compression of said object to
an extent correlated to the inflation pressure of said object
a spring pressed plunger slidable and guided in said housing and
normally positioned to project into said test chamber in the
direction in which the object is compressed, said plunger being
slidable from a predetermined position as it is displaced in said
testing condition by the object being tested, and
measuring means responsive to the displacement of said plunger and
in shiftable relation to a scale calibrated to indicate the
inflation pressure of the object being tested.
Description
SUMMARY OF THE INVENTION
This invention relates to improvements in testers for inflated
items and more particularly to devices for testing the pressure of
tennis balls and racquet balls.
Inflated game balls such as tennis balls and racquet balls are
commonly sold in sealed cans designed to retain the pressure
injected therein by the manufacturer. Thus, a tennis ball which is
removed from its sealed container is subject to loss of pressure
when removed from the can, and particularly is subject to gradual
loss of pressure as evidenced by loss of its bouncing properties as
it is used in play. Professional players discard balls after
playing a few games because the pressure in the balls has dropped
below a selected value, usually below 12 psi. The rate at which
tennis balls lose pressure varies so that there is no standard
length of service which is applicable to all balls even as to the
balls dispensed in the same sealed container.
Ball inflation is now determined by observing or comparing the
bouncing properties of balls or by squeezing or "feeling" a ball in
the palm of the hand of a player. Such bounce, feel and squeeze
tests are unsatisfactory at best and obviously differ in
interpretations by different people and depend upon the degree of
experience and practice which a player or user possesses. Thus,
there is a fine degree of difference between (a) balls which are
acceptable for play, (b) those of lesser pressure but acceptable
for use for practice only, and (c) those which are totally
unacceptable due to low pressure, and different individuals have
different standards so that different individuals testing the same
ball may grade it differently.
The loss of pressure of inflated balls is a fact well known to
tennis players and racquet ball players and various devices are
available on the market designed to pressurize a ball, such as
devices in which a ball is subjected to air pressure. Such devices
operate on the premise that the existence of high air pressure
around a ball will, through osmosis, build up the pressure within
the ball. Most of these devices are ineffective because the average
user does not recognize that a long period of time, such as two or
three weeks, is required for the balls to absorb the higher
pressure in the pressurizer. Also, most of these products do not
actually measure the pressure in the ball. A few devices are
available which act to inflate the ball and to measure the pressure
thereof, but such devices heretofore have been too expensive for
the average tennis player. Another type of device utilizes an
aerosol can containing pressurized air and a sealant, and is
provided with a hollow needle which pierces the ball and inflates
it, relying upon the sealant to reseal the ball when the needle is
withdrawn. Devices of this character include no guide for pressure
measurement and permit over-pressurizing the ball to an extent
rendering it unsuitable for play.
It is the primary object of this invention to provide a device by
which an inflated item can be tested quickly to ascertain the
pressure thereof and determine whether the pressure therein falls
within accepted limits.
A further object is to provide a device of this character which can
be produced economically so that it can be sold at a price which
the average tennis player is able and willing to pay.
A further object is to provide a tester of this character which can
be used quickly by a simple manipulation which provides a quick
pressure indication, so that it can be used during the play of a
game without objectionably delaying the game.
Other objects will become apparent from the following
specifications.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, FIG. 1 is a perspective view of one embodiment of
the invention.
FIG. 2 is a perspective view illustrating commencement of use of
the tester.
FIG. 3 is a perspective view illustrating the test position of the
tester.
FIG. 4 is a top plan view of the device with parts broken away.
FIG. 5 is a vertical sectional view of the tester in idle or normal
position.
FIG. 6 is a vertical sectional view taken along line 5--5 of FIG. 4
and illustrating the test position of the device.
FIG. 7 is a sectional view illustrating a modified embodiment of
the invention.
FIG. 8 is a sectional view similar to FIG. 7 illustrating the
device of FIG. 7 in its test position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The device comprises a housing having a chamber to receive the item
being tested and into which extends a spring urged plunger which
controls a pressure indicating device visible by the user. The
chamber for receiving the test item is so dimensioned that upon
closing of the chamber by the user, as by pressing an open end
thereof against a closure or abutment member, the test item is
deformed and displaces the plunger against the action of its
controlling spring to actuate the indicator in proportion to the
extend of deformation of the test item as determined by its
contained pressure.
Referring to the drawings and particularly FIGS. 1-6 inclusive
which illustrate one embodiment of the invention, the numeral 10
designates a housing which is preferably molded from a rigid
synthetic material or metal. Housing 10 has a cavity 12 open at one
end thereof which is preferably circular when the device is used to
test a spherical member. The cavity has a diameter or shape to
receive and position centrally therein a ball or other inflated
member 14 and has a depth not greater than and preferably slightly
less than the diameter of the ball 14. The walls of the cavity 12
are preferably interrupted at recesses, notches or openings 16,
preferably at opposite sides thereof. A second cavity 18 is open at
the opposite end of housing 10, the same preferably being
cylindrical and concentric with the housing. A central passage 20
is formed in the housing 10 and is open at the cavities 12 and 18
at its opposite ends. A plate 22 is secured on the end of the
housing at which the second cavity 18 opens by screws 23. Plate 22
preferably is provided with a concentric thickened portion 24 of a
size to seat in the open end of the cavity 18 and thus properly
orient the plate 22 to the housing 10. The plate 22 has a central
axial bore 26 therein, axially aligned with the passage 20. Plate
22 is also preferably provided with a central tubular part 28 which
projects downwardly into the cavity 18.
The tubular part 28 of the plate 22 and the passage 20 of the
housing cooperate to slidably receive and to guide a plunger 30
having an enlarged disk portion 32 intermediate its ends which
normally seats on the bottom of the cavity 18 in which it has
clearance. A coil spring 34 encircles the plunger 30 and the
central tubular part 28 of the plate 22, the same bearing at its
lower end upon the disk 32 and at its upper end against the portion
24 of the plate 22. The lowermost end of the plunger 30, i.e. that
portion below the disk 32, is of a length greater than the length
of the passage 20, is slidable in passage 20, and preferably
terminates in a rounded part-sperical end portion 36 which projects
into the cavity 12, when the disk 32 is seated at the bottom of the
cavity 18, to a predetermined extent, such as the extent of
projection illustrated in FIG. 5. The plate 22 preferably includes
an upperwardly projecting rib 38, preferably circular. A
transparent inverted cup shaped member or dome 40 is mounted upon
the margin of the plate 22 as positioned by the rib 38 and forms an
upper chamber 42 of the device.
The upper portion of the plunger 30 above the disk 32 is preferably
provided with a longitudinal rib 44 which is preferably received in
and guided by a groove in the plate 22 and its central tubular part
28. A part 46 projects upwardly and endwise from the plunger 30 and
rib 44 and has a vertical slot 48 in its upper end. Plate 22 is
provided with an upper projection 50 adjacent to the slot in
tubular part 28 which guides the plunger projection 46, and said
projection 50 has a vertical slot 52 therein which is aligned with
slot 48 in plunger 46. A pointer or indicator 54 is pivoted at 56
at an end thereof which fits in the slot 52, said pointer passing
through the slot 48 in the plunger projection 46 and preferably
bearing upon a cross pin 58 extending across the slot 48 of the
plunger projection. The free or indicating end of the pointer 54 is
juxtaposed to a scale 60 which may be embossed or etched in the
dome 40 or upon a member 61 enclosed in selected position within
the transparent dome member 40. The parts are so proportioned that
the pointer 50 will preferably be substantially horizontal to
indicate the low point on the scale 60 when the plunger is in its
normal inoperative position at which the disk 32 seats upon the
bottom of the cavity 18 as illustrated in FIG. 5. The scale 60 will
be of such length that the pointer will reach the high point
thereof only when the maximum expected pressure of an inflated
member being tested is encountered in use.
In the use of the device, the ball 14 is supported upon the surface
of a rigid member 62 which preferably is substantially flat. The
housing 10 of the tester is then applied around the ball at the
cavity 12 as illustrated in FIG. 6, the notches 16 accommodating
the application of the housing around the ball. The user then
applies pressure to the housing 10 to bring the lower end edge 64
of the housing into contact with the member 62 and maintains the
housing in that position while the position of the pointer 54
relative to the scale 60 is observed. The action of lowering the
housing into contact with the member 62 while a ball 14 is confined
within the cavity 12 results in compression of the ball to an
extent determined by the internal pressure within the ball. As the
ball is compressed, the plunger 30 is displaced upwardly in
proportion to the internal pressure of the ball to unseat the
plunger disk 32, compress the spring 34, and elevate the plunger
extension 46 and the pin 56 to thereby tilt the pointer 54
upwardly, as seen in FIG. 6. The scale 60 may be so calibrated as
to indicate the pressure of the ball within (a) a selected range of
acceptable playing pressure which may be indicated at the upper end
of the scale 60, (b) a lesser pressure but sufficient for use of
the ball during practice as indicated in an intermediate part of
the scale, and (c) an unacceptable pressure at the lower part of
the scale. The scale may have any suitable means (not shown)
associated therewith to indicate the range at which a ball is
tested, such as a band of color at the upper end of the scale
indicating a ball which is playable, a second band of color at the
intermediate part of the scale indicating a ball unacceptable for
play by usable for practice, and a band of a third color at the
lower end of the scale indicating an unplayable ball.
It will be evident that the time required to test a ball and
determine its pressure condition and its gradation as between
playable condition and practice condition and unacceptable
condition is very short, so that the use of the tester during a
game to test the balls in play as to their acceptability is so
short that no objectionable delay of the game occurs.
Another embodiment of the invention is illustrated in FIG. 7 and 8.
In this construction, a housing 70 has an open ended test chamber
72 for the ball 74 to be tested and an upper cavity 76 which is
spanned and closed by an upper closure plate 78. A plunger 80 is
slidably received in a passage 82 which is preferably interrupted
by an annular groove housing a sealing ring 84. Plunger 80 has an
enlarged disk 86 intermediate its ends which is normally pressed
against the bottom of the chamber or cavity 76 by a coil spring 88.
A suitable seal 90, such as a ring seated in a groove, extends
around the upper end of the housing and in contact with the upper
closure plate 78 to insure that a liquid 98 contained in the upper
cavity 76 cannot leak therefrom similarly to the seal 84 provided
to resist leakage around the plunger 80.
Closure plate 78 has a passage 92 therethrough displaced from the
center thereof and from the spring 88. A transparent tube 94 is
mounted in passage 92 and projects above plate 78. Tube 94 has
graduations 96 along the length of its projecting portion by means
of which the level of liquid 98 in the tube, which liquid is
preferably colored, can be observed and measured. A transparent
closure or cover 100 is mounted on the upper end of the device. The
upper closure plate 78 is preferably anchored to the housing, as by
anchor screws 102, and the transparent cover is suitably mounted
upon and partially surrounds the upper closure plate.
The use of the device of this embodiment is substantially the same
as use of the first embodiment. The device is placed to enclose
ball 74 to be tested within the test chamber 72, followed by
application and maintenance of pressure endwise upon the housing to
force its end edge 73 against the surface of a supporting member
104 so as to compress the ball 74 and cause it to be indented by
the plunger 80 which is displaced endwise in the housing to an
extent determined by the amount of pressure contained within the
test ball 74. The lower end of the tube 94 is open to the cavity 76
and is normally filled with liquid to a level at or adjacent the
top of the upper closure plate 78. As the plunger 80 is displaced
upwardly by the resistance to compression provided by the test ball
74, liquid 98 will be displaced from the chamber 76 into the upper
portion of the tube 94 at which its liquid level can be
observed.
While the preferred embodiments of the invention have been
illustrated and described it will be understood that changes in the
construction may be made within the scope of the appended claims
without departing from the spirit of the invention.
* * * * *